Waterproof primer cartridge



Nov. 28, 1967 R. 5. NELSON 3,354,827

WATERPROOF PRI MER CARTRIDGE Filed May 2, 1966 5 Sheets-Sheet 1INVENTOR. Richard G. Nelson www w Nov. 28, 1967 R. 3. NELSON 3,354,827

WATERPROOF PRIMER CARTRIDGE Filed May 2, 1966 3 Sheets-Sheet 2 FIG. 4FIG. s

INVENTOR. 'RiChCl rd (5. Nelson Nov. 28, 1967 R. G. NELSON WATERPROOFPRIMER CARTRIDGE 3 Sheets-Sheet Filed May S, 1966 FIG. 8

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FIG. 6

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FIG. 9

INVENTOR. Rlchord 6. Nelson BY 54 g United States Patent 3,354,827WATERPROOF PRIMER CARTRIDGE Richard G. Nelson, Tamaqua, Pa., assignor toAtlas Chemical Industries, Inc., Wilmington, Del., a corporation ofDelaware Filed May 2, 1966, Ser. No. 546,667 7 Claims. (Cl. 10224)ABSTRACT OF THE DISCLOSURE An explosive, waterproof priming device foruse in detonating relatively insensitive explosive charges. The primingdevice includes a main explosive charge disposed in two elongated andwaterproof sections, each of which sections is provided with a flat orotherwise mating face surface, and means for holding the said elongatedsections in face-to-face relationship.

This invention relates to an explosive priming device for use indetonating relatively insensitive explosive charges in a borehole andmore particularly to a waterproof priming device adapted to contain amain charge and a blasting cap, a detonating cord or a booster charge ora combination thereof,

The required water resistance of a priming device or assembly forreliable operation under wet borehole conditions is rather readilyobtained when the main exp osive charge in the priming device is waterresistant such as gelatin dynamites and cast pentolite. However,economic conditions favor the use of relatively inexpensive and lesswater resistant explosives as the main charge, for example,nongelatinous nitroglycerin dynamites, nitrostarch sensitizedexplosives, nitric acid sensitized ammonium nitrate slurries and TNTsensitized explosives. Therefore, in the later case the required waterresistance must be provided by the container for such a primingassembly.

In the prior are, primer assemblies containing main primer chargeshaving little or no water resistance are packaged in metal cans and thedetonator element is generally positioned in or against the side wall ofthe primer can. In the case of using a blasting cap as a detonator, apreformed cap well is sometimes soldered or cemented on the side of thecan to accommodate the cap; whereas, when a detonating cord is used asan initiator an external tunnel plate is attached to the can to containthe cord. Such assemblies provide for only minimum contact between thedetonator element and the main charge in the primer assembly and tend toaffect the balance of the primer assembly causing it to bind to the sidewall when being slide down a borehole.

In accordance with the present invention an explosive priming device isprovided which comprises two elongated sections having mating surfaceswherein each mating surface is provided with at least one mirror imagedepression or groove. The sections may be any shape as long as eachsection is provided with a flat or otherwise mating surface for bringinto kissing contact with another section. A main explosive charge issealed within each of the said elongated sections and means are providedfor holding the said elongated sections in a face to face relationship.

The elongated sections of the present device may be made of any suitablematerials which can be shaped in accordance with the present inventionand which is capable of being formed into a waterproof container forbolding the main charge. For example, the present cartridge may be madeof a plastic material such as polyvinyl chloride, polypropylene orpolyethylene. Alternatively, the present primer cartridge may be madefrom metal, for

Patented Nov. 28, 1967 ICC example, tin plate or aluminum. Each face ofthe two elongated sections that make-up the present cartridge isprovided with suitable mirror image grooves to accommodate a blastingcap, detonating cord or booster or combination thereof. The mainexplosive charge to be used is placed in both elongated sections of thepresent primer through open ends in each of the said sections. After themain charge has been placed in each of the elongated sections the endsthereof are sealed in place so as to yield a water tight seal. The maincharge may be comprised of any suitable explosive material. For example,water sensitive explosives such as a nitric acid sensitized ammoniumnitrate slurry may be used as the main charge. In operation, after thepresent printer has been loaded with the main charge, generally at theexplosive plant, it is shipped to the blasting site where it is to beused. At the time of use a suitable detonator such as a blasting capand/or booster are placed in appropriate grooves in one of the elongatedsections. Then, two sections of the primer are sandwiched together andheld in contact by any suitable means, for example, by a slip fit capover each end thereof, a slip fit sleeve over the length of said primer,by wrapping water-resistant tape around the formed sandwiched cylinderor by gluing or solvent sealing.

A blasting cap suitable for use as a detonator in the present primercartridge may be any of the commercially available waterproof caps suchas a No. 6 or No. 8 blasting cap. A booster suitable for use incombination with the present primer assembly may be any commerciallyavailable booster of a suitable size to fit in the subject primercartridge. Such a booster is water resistant and is comprised of a solidmass of a suitable booster composition containing an explosive such asPETN or pentolite.

The present invention may be more clearly understood by reference to theaccompanying drawings which serve to illustrate several embodiments ofthe present invention and where like parts are identified by similarreference numbers throughout the several views.

FIGURE 1 is a perspective view showing two hemicylindrical sections of aprimer of the present invention.

FIGURE 2 is a partially sectional view of a hemicylindrical section ofFIGURE 1 shown along the line A-A.

FIGURE 3 is a perspective view showing an assembled primer of thepresent invention.

FIGURE 4 is a cross-sectional view of a slip on cap suitable for passingover one end of the sandwiched sections of FIGURE 1.

FIGURE 5 is a cross-sectional view of a slip on cap suitable for passingover one end of the sandwiched sections of FIGURE 1.

FIGURES 6, 7, 8, 9 and 10 are perspective views of the faces of varioushemicylindrical sections of the present invention.

FIGURE 1 shows two separated hemicylindrical sections 11 and 15 of thepresent device having mirror image depressions or grooves 19, 21, 19'and 21 respectively. Sections 11 and 15 are made from a plastic material or metal. The main charge 23 as shown in FIGURE 2 is sealed intoeach hemicylindrical section 11 and 15 by means of ends 13 and 17respectively. The sealing of end 13 and 17 in place may be suitablyaccomplished by heat sealing, solvent sealing or by an adhesive ifsections 11 and 15 and ends 13 and 17 are made of a plastic material. Ifthe primer sections are made of metal, the end seals 13 and 17 may besoldered or rolled in place.

An assembled primer of the present invention is shown in FIGURE 3. Legwires 14 are shown leading through off center hole 2 in cap 1 from ablasting cap sandwiched between sections 11 and 15 in mirror imagedepressions 21 and 21'. A cross section of cap 1 is shown in FIGURE 4.Hole 2 is positioned in cap 1 so as to be in alignment with depressions21 and 21' when sections 11 and 15 are sandwiched together. Hole 3 ispositioned in cap 1 so as to be in alignment with detonating corddepressions 19 and 19 when the primer sections are suitably assembled.Cap 6 shown in FIGURE is provided with hole 7 to be in alignment withdepressions 19 and 19' when fitted over the opposite ends of sections 11and 15 as shown in FIGURE 3.

The faces of hemicylindrical sections of the present primer shown inFIGURES 610 are grooved in various manners to accommodate a plurality ofdetonating means. The face of hemicylindrical section 25 in FIGURE 6 isprovided with detonating cord depression 27 and blasting cap groove 29.FIGURE 7 shows hemicylindrical section 31 provided with boosterdepression 33, blasting cap groove 35 and detonator depression 37.Hemicylindrical section 39 shown in FIGURE 8 is provided only with capwell 41. A hemicylindrical section 43 of a primer of the presentinvention shown in FIGURE 9 is provided with a dctonating cord groove49, blasting cap well 45 and a depression 47 to accommodate a booster atthe end of well 45. Hemicylindrical section 51 shown in FIGURE isprovided with a groove 53 to receive a detonating cord.

What is claimed is:

1. A cylindrical explosive priming device which comprises, two elongatedhemicylindrical waterproof sections each having mating surfaces andcontaining an explosive charge sealed therein, each of said matingsurfaces provided with at least one mirror image depression, and meansfor holding the said elongated waterproof sections together with contactof said mating surfaces.

2. An explosive priming device of claim 1 wherein the depressions areadapted to hold a blasting cap, a deto nating cord, or a booster chargeor a combination thereof.

3. An explosive priming device of claim 1 wherein the elongated sectionsare held in face to face relationship by means of a slip on cap overeach end of said sections.

4. An explosive priming device of claim 1 wherein the hemicylindricalsections are made of a plastic material.

5. An explosive priming device of claim 1 wherein the hemicylindricalsections are made of a metallic material.

6. An explosive priming device of claim 1 wherein the hemicylindricalsections are held in face to face relationship by means ofwater-resistant tape.

7. An explosive priming device of claim 1 wherein the explosive chargeis a water sensitive explosive.

References Qited UNITED STATES PATENTS 3,183,836 5/1965 Griffith 102243,212,438 11/ 1965 Lawrence 10224 3,233,688 2/1966 Bell 10224 FOREIGNPATENTS 1,295,471 5/ 1962 France.

SAMUEL FEINBERG, Primary Examiner.

BENJAMIN A. BORCHELT, Examiner.

V. R. PENDEGRASS, Assistant Examiner.

1. A CYLINDRICAL EXPLOSIVE PRIMING DEVICE WHICH COMPRISES, TWO ELONGATEDHEMICYLINDRICAL WATERPROOF SECTIONS EACH HAVING MATING SURFACES ANDCONTAINING AN EXPLOSIVE CHARGE SEALED THEREIN, EACH OF SAID MATINGSURFACES PROVIDED WITH AT LEAST ONE MIRROR IMAGE DEPRESSION AND MEANSFOR HOLDING THE SAID ELONGATED WATERPROOF SECTIONS TOGETHER WITH CONTACTOF SAID MATING SURFACES.